It's been almost a century since the outbreak of Spanish flu in 1918, arguably our most significant struggle with pandemic influenza. Dave Gruber, senior assistant commissioner for the division of health infrastructure preparedness and emergency response for the state of New Jersey, briefly chronicles the breadth of our 20th century pandemic encounters, and examines how these events apply to our evolving understanding of the public health consequences. Very simply, what defines a case of pandemic influenza? Mr. Gruber also updates us on the details of a potential vaccine for prospective Avian flu scenarios. Susan Dolan hosts.